This episode of NOVA explores the possibility that chimpanzees and other primates can use language to communicate with humans. The program introduces several researchers who have spent their careers collecting data about the behavior and learning patterns of these animals. Through the use of sign language, computer lexigrams, and visual aids, the researchers have compiled a large body of evidence showing that the animals can communicate. Some of this evidence relies on subtle observation and intensive contact with the animals.

In addition to exploring the scientists' theories and results, NOVA raises questions about the responsibilities of researchers. Most of the chimps featured in this program were reared in human-controlled environments and studied for periods of many years. Because chimpanzees raised in captivity become dependent on humans for their continued survival—and chimps can live over 40 years—scientists must be prepared to care for the animals in a humane manner long after the research is finished.